1. Technical Field
The present disclosure relates to light emitting diode (LED) light sources and a backlight having an LED light source. The backlight can typically be used in a liquid crystal display (LCD).
2. Description of Related Art
In general, an LED light source includes an LED die. The LED die includes an emitting surface. Due to the high refractive index of most LED materials (typically greater than 3), light rays generated in the LED die incident on the emitting surface at an angle greater about 20 degrees experience total internal reflection (TIR) and do not pass through the emitting surface. This limitation makes the LED die a highly directional light source. To improve the directional property of the LED die and also to protect the LED die from being damaged, the LED light source also includes a dome-shaped encapsulation. The LED die is encapsulated by the dome-shaped encapsulation. One of the shortcomings of such a dome-shaped encapsulation in an LED light source is that the dome-shaped encapsulation typically does not significantly change (i.e., spread) the light intensity distribution of the LED die. As a result, the uniformity of light output by the LED light source is rather low, and may not adequately meet performance requirements when the LED light source is applied to a backlight of an LCD.
Therefore, it is desirable to provide an LED light source and a backlight which can overcome the above-mentioned problems.